Secondary displacement in distal forearm fractures in children: adequate positioning of the wrist in the cast is more important than cast index.

The objective of this study was to assess whether the positioning of the wrist joint in the cast in such a manner that it counteracts the direction of angulation of fragments is more important than the cast index in the prevention of secondary displacements in distal forearm fractures. A retrospective review of all pediatric patients (0-16 years of age) who were hospitalized in our institution with displaced fractures of the distal forearm (either isolated fractures of the distal radius or both bone fractures) who underwent subsequent closed reduction and splinting in the period from August 2018 to October 2020. Patients with physeal fractures and open fractures, and skeletally mature patients were excluded from the study. Patients were divided into two categories - the first one in which the cast index was below 0.9 and the second in which it was above 0.9. In each category, we have identified two groups of patients - the first one in whom the wrist joint was positioned in such a manner that it counteracts the direction of angulation of fracture fragments and the second one in whom the wrist joint was in a neutral position. The two groups in each category have been compared according to age, sex, initial angulation, fracture type (isolated radius or both bone fractures), displacement type (angulation or complete dislocation) and the rate of secondary displacement. In both categories, the two groups were comparable according to age, sex, initial angulation, fracture and displacement type. In both categories (cast index below 0.9 and cast index above 0.9), a statistically significant higher portion of patients with secondary displacement was identified in the group of patients who had the wrist joint in a neutral position ( Z = -2.1997; P = 0.0278 - for cast index <0.9 and Z = -2.1672; P = 0.030216 for cast index >0.9). Our research supports the notion that positioning of the wrist joint in the position that counteracts the force that leads to angulation of fracture fragments is more important than the cast index in the prevention of secondary displacements in pediatric distal forearm fractures.